Toxicity of nanoparticles to cold-adapted denitrifying bacteria and the denitrification process and the countermeasures

Abstract:

Biological denitrification is cost-effective, efficient, and environmentally friendly, which thus has broad prospects in the wastewater treatment. At the moment, most of the available denitrifying microorganisms in wastewater treatment are mesophilic bacteria. However, the denitrification is significantly inhibited in the case of low temperature. The cold-adapted denitrifying bacteria, with tolerance to low temperature and high efficiency in denitrification, have attracted the interest of scholars. Moreover, the nanoparticles (NPs) are widely used in biology, agronomy, medicine and other fields, which, however, are inevitably released to water and soil in the production, storage, and usage of NPs-containing products. Massive accumulation of NPs in the water will hinder the denitrification of microorganisms, posing a challenge to wastewater treatment and arousing the concern of scholars. The denitrification process of cold-adapted bacteria, the toxicity of NPs to the denitrification, and the countermeasures have been studied. On this basis, this article describes the cold-adapt mechanism and denitrification process of the cold-adapted bacteria and discusses the toxicity of NPs to the denitrification process and the countermeasures, which is expected to lay a theoretical basis for the use of microorganisms to treat nitrogen-polluted wastewater containing NPs in a low temperature environment.